The Secondary Mirror Cell Assembly ("M2CA") Planning Study RFP Clarifications and Exceptions
The following are the TMT responses to requests for clarifications or exceptions of the M2CA RFP:
Q. Will TMT use a commercial contract in the event this effort is privately funded?
A. Yes. If either the M2CA or M3S Planning Study are funded with private funds, TMT will utilize its standard commercial terms and conditions found at the following link:
TMT Commercial Firm Fixed Price Contract
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Q. In regards to the Baseline Design Concept Development, will TMT deliver CAD models of the conceptual design to the Contractor for evaluation?
A. TMT will provide some CAD models and analysis reports to the contractors that are pertinent to the Study Phase. TMT will also provide information from the Conceptual Design Review for the previous Gregorian Telescope design. This information will be for reference only and does not necessarily represent the Ritchey Chrétien Telescope design.
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Q. Given that the design maturation will only be at the Planning Study phase, there will be a relatively high level of uncertainty in specifying all FDFP hardware, services, resources, etc. Costing the FDFP with greater than 90% confidence will be a challenge. Would you please comment on the level of detail expected in the FDFP cost estimate?
A. The level of detail should be sufficient to allow costs to be estimated by the most appropriate means available for each subsystem. This may be to define the key parameters (e.g. kilograms of steel, number of actuators, etc.) for a parametric estimate, or to estimate adjustments relative to similar systems previously delivered, or in some cases to do a bottom-up estimate.
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Q. May future revisions of the M2 DRD be revised to add a “Verification Method” Matrix as an Appendix, where a verification method is identified for all requirements (e.g. Analysis, Acceptance Test, Demonstration Test, etc.)?
A. During the preliminary design phase, the contractor will be required to develop its own verification matrix to verify to TMT that the requirements will be met. The verification methods are to be proposed by the contractor.
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Q. Do the requirements referenced by the “(TBC)” notation require confirmation by TMT or by the Contractor?
A. It is the responsibility of TMT to resolve all “(TBC)” notations in the requirements documents.
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Q. In the M2S DRD, Section 3.1.6 [REQ-2-M2-0215] states “The M2S shall survive earthquake dynamic accelerations equivalent to a static acceleration of 6 g (TBC), due to a maximum likely earthquake described in [REQ-1-ORD-1400].” What must be confirmed? Must TMT confirm the 6 g requirement or does the Contractor have to confirm the survivability?
A. TMT will confirm the requirements. The Contractor will confirm the survivability.
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Q. In regards to the M2 DRD, what level of MTBF analysis and documentation is expected to display compliance with requirement [REQ-2-M2-0155]? In the Study Phase? Preliminary Design Phase? Will compliance with MIL-HDBK-217F RELIABILITY PREDICTION OF ELECTRONIC EQUIPMENT be expected and/or desired for electronic components employed in the M2CA design?
A. Most of this will have to be “Engineering Estimates” with a good “Basis of Estimate.” A MIL or NASA spec is not likely to be cost effective for this project.
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Q. Please define a “failure” as it pertains in the M2S DRD. Does departure from the structure function constitute a failure? Requirement [REQ-2-M2-0630] states, “The M2SS shall be robust, and shall be able to continue operation in case of failure of an actuator, even in the case of an actuator maintaining its maximum force.” This implies that the telescope will continue operation after the failure of one actuator. At what point is observing aborted due to M2S performance?
A. Science data is the merit function for degradation. Some failures can prevent data collection and some failures can degrade data. In the context of this requirement, a moderate degradation of overall telescope performance would not be considered a failure. Contractor shall identify potential failures and evaluate the effect on telescope performance (science data collection). TMT will evaluate the effect on a case-by-case basis to determine if risk mitigation is required.
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Q. The 20Hz lowest resonant frequency M2CA requirement will be challenging to achieve for an optical/opto-mechanical structure of this size and complexity. We propose that the “higher than 20Hz” requirement be designated a goal rather than a requirement.
A. Noted. This may be changed when the consequences are better understood.
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Q. Do you want to preclude the option of studying other materials as an option for the mirror substrate?
A. TMT studied other materials for the mirror substrate in the Conceptual Design Phase and concluded that they did not appear to be cost effective. Any proposal to use a material other than a zero-expansion glass or glass ceramic must be justified on a cost-performance basis.
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Q. Will an Adaptive M2 (AM2) ever be included in the Study Phase?
A. The AM2 was deleted from the TMT Project for First Light due to funding constraints. It will not be part of the M2SCA Study Phase.
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Q. In the M2S DRD, under the Discussion section for [REQ-2-M2-0415]: The anticipated range of ambient air temperature gradients is stated in REQ-2-M2-1080. Other more localized gradients could be produced by the M2CA and the M2SS. Should the requirement noted in the discussion be REQ-2-M2-0110 and not REQ-2-M2-1080?
A. Yes
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Q. It seems that requirement [REQ-2-M200425] should be subject to the chosen substratum material as opposed to a general requirement. Is there a proposed acceptance test to verify [REQ-2-M2-0425]?
A. This requirement is based on the use of a glass or glass ceramic mirror substrate. The blank supplier should propose the verification method, but we anticipate it should be verified by testing (i.e., birefringence) combined with modeling, as appropriate.
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Q. In regards to [REQ-M2-0645], [REQ-M2-0650], [REQ-M2-0655] and [REQ-M2-0660], of the M2 DRD, does the TMT conceptual design identify a sensor/feedback mechanism to verify M2M location and orientation relative to the interface between the M2CA and M2PA? Are there M2 location measurements, to within 500nm, inherent in the telescope TMT Alignment and Phasing System? Alternatively, is it the responsibility of the contractor to define the measurement and feedback system to verify and correct the positional location of the M2 mirror?
A. This requirement is necessary to ensure that the position of the M2M can be controlled by the M2PA using a look-up table, therefore the stiffness and repeatability of the mirror defining system are important. The Contractor shall propose how it will verify this requirement, but TMT anticipates it will be by design analysis combined with tests that verify the stiffness of the as-built defining system.
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Q. Please comment on the level of acceptance testing required, expected, and/or recommended to verify M2M surface figure after integration into the M2 cell assembly? As implied by the TMT Metrology Study for M2 and M3, a localized testing of the mirrors in their respective cells could be performed as opposed to full aperture test or sub-aperture stitching.
RFP Exhibit D, The TMT Metrology Study for M2 and M3 states, “However, if the goal of the test is to sample some regions on the surface to look for small scale errors due to mounting problems, many of the difficulties go away.” This statement implies that subaperture testing of the M2M surface for small scale errors, without completing subaperture stitching, could be sufficient for surface figure acceptance testing for M2 in its support cell. Integrated testing with M2 installed in the TMT system could then be completed for final iteration on the M2CSC LUT.
A. Stitching or other means to test the full aperture will be required to meet the acceptance level tests and to develop the LUTs. Variations of support print-through with zenith angle may potentially be measured without stitching.
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Q. In regards to [REQ-2-M2-0690] of the M2S DRD, the term “offsets” are assumed to mean “incremental changes to LUT set points,” as implied in section 2.2 SYSTEM FUNCTIONS, but not explicitly defined with reference to the M2CSC. In the discussion of the M2CSC, the term “force deltas” is used to refer to a similar concept.
A. Incremental changes in the LUT set points will result in force deltas, if force actuators are used in the mirror support subsystem.
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Q. In regards to [REQ-2-M2-0785] of the M2S DRD, will the TMT be providing a global interface control document to which the M2CSC will have to adhere?
A. Yes.
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Q. In regards to [REQ-2-M2-0810] of the M2S DRD, will the TCS provide temperature and elevation data to the M2CSC with the power-up command message, or as a separate message immediately following the power-up command? Or will the power-up command only occur under a specific controlled elevation and temperature condition?
A. This level of detail is not available at this time. It will be in the M2S to TCS ICD. The contractor may assume that any necessary data will be made available and that the power-up command can occur at any elevation angle and temperature.
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Q. In regards to [REQ-2-M2-0815] of the M2S DRD, does the 30 second initialization time mean that the M2S should be thermally equilibrated at the end of the initialization sequence? Alternatively, do all M2 performance specifications have to be within requirements at the end of initialization, or does it just mean that the support structure is “ready to operate”.
A. At the end of the initialization sequence the M2CA shall be ready to operate, it is not expected to be thermally stable within 30 seconds; therefore additional time may be required before it meets all performance specifications.
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Q. Is the M2CSC allowed to actively control the flow of coolant? If so, then it loses control when it is powered down, and when it is powered up again, the thermal gradients in the mirror may not be correctable within the 30 second time frame.
A. The M2CSC does control the flow of the coolant. TMT assumes the coolant will not be required to cool the mirror. It will cool the electronics and it may cool the actuators but the goal is to not have the actuators require cooling. There will be time allocated for thermal stabilization (~ 10 minutes).
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Q. In regards to [REQ-2-M2-0875] of the M2S DRD, arbitrary control of individual actuators may not be possible via the TCS due to safety or fault restrictions (such as interactuator stroke limit). Some encapsulation is necessary. More encapsulation may be desired to reduce the overall complexity that is visible to the TSC.
A. TCS control will not override safety and fault restrictions, but a diagnostic and calibration mode is necessary where the TCS will have access to control individual actuators and read individual sensors.
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Q. In regards to the Discussion Section of [REQ-2-M2-0785] for the M2S DRD, is there a budget for the amount of waste heat that may be dumped into the glycol-water coolant by the M2CSC?
A. Not at this time. A power budget will be available for the PDP. The contractor may assume that the facility will supply adequate volume of coolant.
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Q. In regards to Section 4.3 of the M2CA PDP, it states that the Contractor shall design the M2 Support System to meet all the M2CA Requirements. Contractor shall perform detailed analyses to demonstrate compliance with the M2CA Requirements, including: (a) analysis of the M2SS performance over zenith angles ranging from 0 to 90 degrees and temperatures ranging from 22 to 2 degrees Celsius.
The definition of temperature range for M2CA requirements listed in section 4.3 of the M2CA PDP seems to be inconsistent with section 3.1.2 Environmental Constraints of the Observatory Requirements Document (TMT.SEN.DRD.0.5.001.CCR16). The Observing Operation Conditions specified in section 3.1.2.3 of the Observatory Requirements Document list the ambient temperature range as 2°C to 15°C.
A. The 22 degrees C refers to the temperature of the optical shop where the M2CA will be assembled and tested.
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Q. In regards to Section 4.6 of the M2CA PDP, does TMT expect the Study Phase Conceptual Design to address the M2CALF or does the cell design simply need to comply with [REQ-2-M2-0670]; The M2C shall incorporate features that can interface with the M2 Cell Assembly Lifting Fixture (M2CALF)?
A. M2CALF shall be conceptualized, in the Study Phase, only to the extent needed for the cost and schedule estimates. TMT believes the design of the M2CA must be closely coordinated with the design of the M2CALF and therefore it is appropriate for both to be designed by the same contractor.
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Q. In regards to Section 4.7 of the M2CA PDP, does TMT expect the Study Phase Conceptual Design to address the M2MLF?
A. M2MLF shall be conceptualized, in the Study Phase, only to the extent needed for the cost and schedule estimates. TMT believes the contractor will require similar fixtures during fabrication and testing, and that it will be cost effective for the M2MLF to be designed and produced by the Contractor for subsequent use at the observatory.
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Q. Is it necessary to perform a conceptual design of the coating fixtures?
A. No, it is not necessary to perform conceptual design of coating fixtures.
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Q. In regards to Section 5.2 of the M2CA PDP, please comment on the number of 2D drawings expected at the completion of the PDP (other than the M2 Mirror Blank referenced in section 4.1).
A. Fabrication drawings are not required in the PDP. Layout drawings and interface drawings are required to the extent necessary to describe the preliminary design, to support the analysis used to flow requirements down to the lower levels and to provide an adequate cost and schedule quote for the FDFP.
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CLARIFICATION:
APPENDIX A:
SUMMARY OF OAD AND ORD REFERENCES TO THE M2S
1. The listing for [REQ-1-OAD-1810]: M2 maximum cross section, should be [REQ-1-OAD-1080] and the section referenced in M2S DRD should read 3.2.1.
2. The listing for [REQ-1-OAD-1815] M2 average drag coefficient, should be [REQ-1-OAD-1085] and the section referenced in M2S DRD should read 3.2.1.
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CLARIFICATION:
1. All proposals must be prepared with the understanding that they will be distributed amongst and between the pertinent representatives of the TMT Project members. This includes any and all consultants that the TMT Project engages to support its review of the proposals.
2. The “Total Estimated Cost of the Proposal” in the Offer Submittal Form refers to the quoted price of completing the planning study.
3. Proposals may be submitted with sections in other Microsoft Office formats outside of Microsoft Word. If there is an issue with that format, TMT will let you know and we will mitigate it accordingly.
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Suppliers are encouraged to check this page regularly for any modifications, additions or new information regarding the TMT M2CA Planning Study RFP.
Thank You,
The TMT Project
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